Method of forming fibers



Dec. 12, 1961 c. J. STALEGO I 3,012,281

METHOD OF FORMING FIBERS Filed Feb. 25, 1955 5 Sheets-Sheet l IN V ENTOR. 106 (bar/e5 JSfo/ej 0 C. J. STALEGO METHOD OF FORMING FIBERS Dec.12, 1961 5 Sheets-Sheet 2 Filed Feb. 25, 1955 INVENTOR. 6&ar/ejrffifa/gyo W AT T YS.

Dec. 12, 1961 c. J. STALEGO METHOD OF FORMING FIBERS :s Shets-Sheet 5Filed Feb. 25, 11955 INVENTOR. (kw/e5 {fife/ 0 BY W 9 M ATTYS.

nited States Patent Ofiice 3,012,281 Patented Dec. 12, 1961 ware FiledFeb. 25, 1955, Ser. No. 490,458 1 Claim. (Cl. 18-473) This inventionrelates to method of forming fibers and more especially to a method offorming fibers from heatsoftenable, fiber-forming material through theapplication of centrifugal forces and high velocity gaseous blasts tothe softened material.

The invention embraces a method of forming primary fibers fromheat-softened material such as glass by delivering a viscous body orstream of heat-softened mineral material such as glass, slag or fusiblerock to a zone, applying centrifugal forces at the zone to form primaryfilaments or thin elongated bodies of the material and delivering theprimary filaments or elongated bodies into a blast or blasts forattenuating the filaments or bodies to fine fibers of varying lengths.

An object of the invention is the provision of a method involving theapplication of centrifugal forces and an attenuating blast or blasts toheat-softenable material wherein viscous heat-softened material such asglass is delivered to a rapidly rotating surface causing the glass tomove in generally radial directions under the influence of centrifugalforces from the rotating surface in the form of elongated bodies orprimary filaments, burning a combustible mixture in a confined zone andprojecting the products of combustion through a restricted orifice rorifices as intensely hot blasts into engagement with the elongatedbodies or primary filaments for attenuating the material to fibers, therestricted orifice construction being configurated, shaped or patternedto obtain a blast or blasts of exceedingly high velocity with a minimumof turbulence whereby attenuation of the elongated bodies to fibers isgreatly improved and the thermal efficiency is increased over priormethods.

Another object of the invention involves the application of an intenselyhot, high velocity, gaseous prirnary blast to elongated bodies offiber-forming material formed by centrifugal forces to attenuate theelongated bodies to fibers, the method including one or moresupplemental gaseous blasts formed of burned gases or products ofcombustion correlated with the primary blast to avoid projection of thebodies entirely through the primary blast and thus assure properattenuation of all of the elongated bodies to fibers.

Another object of the invention is the provision of a method of forminghigh velocity attenuating blasts and particularly a plurality of blastsarranged in an annular pattern produced by burning a combustible mixturein an annularly shaped, internal-combustion chamber and projectingtheintensely hot products of combustion through a plurality of orificesor outlets to provide attenuating forces operative in an annularlyshaped zone for attenuating heat-softened, material, such as glass, tofibers.

Another object of the invention resides in an apparatus including meansfor forming and directing a substantially annularly shaped blast ofintensely hot gases into contact with elongated bodies or primaryfilaments of fiber-form ing material projected into the blast under theinfluence of centrifugal forces for attenuating the material to finefibers and directing a secondary blast or blasts from a supplementalburner or burners in a direction generally opposing the path of travelof the primary filaments or bodies in order to prevent traverse of thefilaments or bodies through the high velocity blast and assist inbending the primary filaments or bodies in the direction of travel ofthe gases of the annularly shaped blast to attain a high efliciency ofattenuation and increase the production of fine fibers.

The method of the invention of producing fibers from heat-softenablefiber-forming material such as glass is inclusive of the steps ofdelivering a stream of the material onto a rotating surface, the forcesof rotation distributing the material outwardly of the surface in theform of primary filaments, and engaging the primary filaments with anannularly shaped gaseous blast of intensely hot gases provided byburning a combustible mixture in an annular region, the gases of theblast engaging the primary filaments in directions substantially normalto their paths of movement from the rotating surface to attenuate theprimary filaments to fibers, and burning combustible mixture in a secondannular region providing a second gaseous blast, the gases of which aredirected generally toward the rotating surface so that filaments whichmay penetrate the attenuating blast are redirected by the second blastinto the attenuating blast.

Further objects and advantages are within the scope of this inventionsuch as relate to the arrangement, operation and function of the relatedelements of the structure, to various details of construction and tocombinations of parts, elements per se and to economics of manufactureand numerous other features as will be apparent from a consideration ofthe specification and drawing of a form of the invention, which may bepreferred, in which:

FIGURE 1 is an elevational view of one form of apparatus for carryingout the method of the invention, certain parts being shown in sectionfor purposes of illustration;

FIGURE 2 is a smtional view taken substantially on the line 22 of FIGURE1;

FIGURE 3 is an enlarged, fragmentary sectional View of a portion of theannular blast-producing burner of FIGURE 1 showing a form of restrictedgas discharge passage or orifice construction;

FIGURE 4 is a view similar to FIGURE 3 illustrating a modified form ofgas discharge passage for the burner;

FIGURE 5 is a view similar to FIGURE 3 showing another form of gasdischarge passage or orifice for a burner;

FIGURE 6 illustrates an annular burner provided with a plurality of gasdischarge passages for producing a composite blast;

FIGURE 7 is an elevational view, partly in section, illustrating afiber-forming apparatus embodying means for producing main andsupplemental blasts for forming fibers from centrifuged bodies offiber-forming material;

FIGURE 8 is an enlarged fragmentary view of a portion of theconstruction illustrated in FIGURE 7 showing the relation of the mainand supplemental burners and gas discharge passages;

FIGURE 9 illustrates the main blast-producing burner and supplemental orantipenetnation blast burner embodying modified forms of gas dischargepassages or orifices;

FIGURE 10 is a view similar to FIGURE 9 showing modified forms of gasdischarge passage or orifice constructions for the main blast andsupplemental blast burners;

FIGURE 11 is a view similar to FIGURE 10 showing another arrangement ofgas passage or orifice construction for the main blast and supplementalor anti.- penetration blast burners;

FIGURE 12 is a view illustrating a burner embodying a plurality ofrestricted orifices or passages arranged in an annular pattern fordischarging gases from the burner in the form of high velocity blasts;

FIGURE 13 is a horizontal sectional view taken sub stantially on theline 13-13 of FIGURE 12;

FIGURE 14 is an enlarged sectional view through T ity attenuating blast.

. 3 V the burner orifice construction, the same being takensubstantially on the line 14-14 of FIGURE 13, and

7 FIGURE 15 is a view similarto FIGURE 13 showing a modified form ofmultiple gas passage or orifice construction for the burner.

K 'I'he'apparatus in which the invention is embodied is inclusive of ameans for supplying molten glass or other heat-softenable material-to adistribution zone, the latter including a. rotor or spinner adapted forreceiving the stream of molten material and projecting or dischargingprimary filaments or elongated bodies of glass or other fiber-formingmaterial from its periphery under the influence of centrifugal forces,and an arrangement for applying gaseous blasts as attenuating forces tothe primaries or bodies for forming the same into comparatively longfine fibers of varying lengths. The elongated bodies primary filamentsare quite viscous as they enter the blast.

Several forms of internal-combustion burner and gas passage or orificeconstructions are shown in the drawings wherein primaries or elongatedbodies of 'fiberforming material are subjected to the heat of one ormore streams or blasts of intensely hot gases to raise the temperatureof the bodies to attenuating temperature, the intensely hot, highvelocity blast or blasts or burned gases engaging the primaries orbodies of fiber-forming material in a manner to change or modify thedirection of travel of the primaries or bodies in drawing or attenuatingthe same to fine fibers of one-half micron or more in diameter.

FIGURE 1' is illustrative of an apparatus embodying one form of theinvention in carrying out the method of forming fibers through theutilization of centrifugal forces and intensely hot, high velocitygaseous blasts. In FIGURE 1 there is illustrated a forehearth or re- 7ceptacle of a melting furnace containing a supply of moltenfiber-forming material such as glass. The forehearth 10 is equipped witha feeder or bushing 14 for delivering or discharging a stream 16 'ofmolten glass or other fiber-forming material in flowable condition.

The centrifugal means for forming primaries or elongated bodies from thestream 16 is disposed beneath the feeder Hand is supported upon a frame17. The cen-' trifugal apparatus is inclusive of a spinner or rotor 20having a peripheral zone provided with a plurality of small openings 24.The spinner 20 is mounted on or carried by ashaft 26 vjournaled inbearings contained within. a suitable housing 28. The shaft 26 isprovided with pulleys or sheaves 30 driven by belts 32 from a suit ablepower means, for example, an electric motor 33.

Disposed within the hollow shaft 26 is a' tubularly shaped burner 34provided with an inlet 35 for the introduction of a fuel-and-air mixtureinto the burner 34. The burner is formed with a hollow central 'zone toaccornmodate the delivery of the stream 16 of glass into the interior ofthe spinner or rotor 20. The burner is provided with a water-cooledjacket 38 having an inlet 7 duct 40 andan outlet duct 41 for conveyingwater from a supply through thejacket 38 and =away'from the jacket.

Disposed adjacent and surrounding 'aportion of the spinnerztl is a meansfor burning a combustible mixture in a confined zone and discharging theintenselyf'hot burned gases or products of combustion as a high veloc-The means illustrated in FIGURE 1 is in the form of an'annularly shapedburner 44'which is connectedwith one or more pipes or ducts 46 forconveying a fuel-and-air mixture into a confined zone 'or combustionchamber 48 whichlis of annular shape;

A "If desired, the confined zone or combustion chamber 48 may be formedof several 'sections' or compartments defined by radially arrangedpartitionspeach compartment or section being supplied with"fu'el-and-air' mixture through individual ducts similar to the duct 46.In

order, to prevent ignition" of the mixture in the duct} 46, a firescreen such as a perforated wall (not shown) is disposed at the entranceof the mixture into the combustion zone 48.

The fuel-and-air mixture is substantially completely burned within theconfined zone or chamber 48, the lower wall of whichv is provided with arestricted gas discharge passage, orifice or outlet 50. The annularburner 44 is enclosed within a metal jacket or casing 52, the combustionchamber 48 being bounded by refractory walls 54 disposed within themetal casing 52. In the embodiment shown in FIGURE 1, the gas dischargeoutlet is of annular shape or character which provides an annularlyshaped, downwardly directed blast adjacent the periphery of the spinneror rotor 20. A metal jacket or hood 56 is secured to the burner 44 whichserves to control or restrict induced air flow caused by rapid travel ofthe gases of the blast.

The burner 34 is of multiple-walled construction having a hollow centralzone to admit the flow of the stream 16 of glass and to form anelongated gas-conveying chamber surrounding the control zone. Thefuel-andair mixture, admitted to the burner 34 through the mixture inlet35, is dischargedinto the spinner through a perforated end cap orconstruction .60. The gas-and-air mixture delivered to the burner 34preferably burns exteriorly of the, outlet formed by the perforatedcap'il. The burner 34 serves as a preheating burner for elevating thetemperature of the spinner 21! when initiating the operation of thefiber-forming devices and may also be utilized to increase or controlthe temperature of'the glass or' other fiber-forming material deliveredinto the spinner 20.

The stream 16 of glass from the feeder or bushing 14 flows into or isdelivered through the hollow interior of the burner34 and impinges upona glass-distributing means or slinger plate 62. The slinger plate 62 andspinner 2,0 rotate as a unit at a speed upwards of 3000 r.p.m. or more.

During rot-ation'of the spinner and slinger plate, the molten glassfalling onto the slinger plate 62 is moved outwardly oftthe axisof'rotation of the spinner under the influence of centrifugal forcestoward the band-like portion 64 defining the periphery of the spinneratits greatest diameter. The molten glass delivered outward-ly by theslinger 62. flows over the extent of the band 64 and moves outwardlythrough the small-diameter openings 24 in the form of a plurality ofelongated bodies, primaries, primary filaments or fibers 65 which arecomparatively viscous but are of a temperature above the solidificationtemperature of' the glass.

The bodies-or primaries 65' move outwardly relative to the axis ofrotation of. the rotor 20 in directions determined by the resultantof'thecombined centrifugal and tangential forces and travel into the pathof the blast of gases projected fromthe chamber 48 through therestricted orifice 50. The orifice is disposed so as to project theblastgenerally downwardly, concentric with and adjacent to the peripheryof thespinner 20'and into ena the velocity of the gases of the blastbends the primaries downwardly, attenuating them into finefibers 68formed in a generally cylindrical configuration. v

' The fibers are of varying lengths and may be upwards of 18." or morein length. The cylindrical formation or pattern of the fibers isreferred to as a beam of fibers 79.

The shape and characteristics of the orifice 50 in the burner wall arehereinafter described in detail and the orifice 50 is fashioned toincrease or augment the velocity of the gases fdrming the blast ascompared with the gas velocities from conventional orifices.

j The shield '56'serves to control induced air set up by the velocity ofthe blast to avoid impairment of the. engagementofthe blast with thebodies or primaries 65. The

hollow beam of fibersjiimoves downwardly through housing or enclosure72,and the'fibers thereof are collected in amass or mat formation upon asuitable surface, for

example, the upper fiight 74 of an endless conveyor 76, the conveyormoving in a righthand direction as viewed in FIGURE 1. A suction box 78is disposed beneath the flight 74 of the conveyor and is connected bymeans of a tube or duct 86 with a blower (not shown) or source ofsuction or reduced pressure effective in the receptacle or box 75 tofacilitate collection and orientation of the fibers upon the collectingsurf" A binder or adhesive may be appl d to the beam of fibers duringthe travel or" the fibers to the collecting surface or may be applied tothe fibers after they have been deposited upon the collecting surface.As illustrated in FIGURE 1 a binder applicator 84 is disposed within thebeam of fibers and is supplied with hinder or adhesive from a supplythrough a duct 86. As illustrated, the applicator is formed with aplurality of orifices 87-throngh which a liquid binder is dischargedradially onto the fibers of the beam. At the zone wherein the duct 86projects through the beam of fibers, the duct may be flattened to theconfiguration illustrated at 88. it is to be understood that if desired,powdered or comminuted binder may be delivered onto the fibers and latercured by conveying the mat of binder-coated fibers through a heatedzone.

The passage or orifice 50 formed in a lower Wall of the refractory 54through which the burned gases from the chamber 43 of the burner 44 aredischarged as a high velocity blast is shaped to a configuration toincrease or augment the velocity of the gases projected from the burneras compared with conventional orifices. One form of orifice foraccomplishing this result is shown in FiGURE 1 and in enlarged sectionin FIGURE 3. The orifice or gas passage 50 is formed, curved orarcuately shaped to conform generally to or be concentric with theperipheral contour of the spinner or rotor 21 whereby the arcuatelyshaped blast is directed in a path generally parallel with the axisofthe rotor and in an annular zone adjacent the outer wall or band 64 ofthe rotor.

The annular side walls 90 and 91 forming the passage or orifice 5B are,in cross section, disposed in diverging relation as illustrated inFIGURE 3 to facilitate the flow of burned gases through the orifice witha minimum of frictional resistance so that a blast of exceedingly highvelocity is obtained for attenuating engagement with the elongatedbodies or primaries projected outwardly through the openings 24 in theperipheral band 64 of the rotor. The angular or divergent relation ofthe walls 99 and 91 defining the passage 59 provides a passage ofvarying cross-sectional area in a downward direction, providing a blastof gases traveling at high velocities.

FIGURE 4 is a view similar to FlGURE 3 illustrating anotherconfiguration of gas passage or orifice 94 in the wall of an annularburner 44a. in this form the orifice includes a narrow, band-likeportion 95 of constant width and angularly disposed walls 96 and 97which are arranged in divergent relation from the band portion 5 to theexterior surface 98 of the burner 44. The Zone or band 95' of thepassage provides a zone of greatest restriction and, in conjunction withthe angularly disposed walls 96, provides an annular passage ofgenerally Venturi shape in cross section which facilitates high-velocityflow of gases from the chamber 48a through the passage.

Being of varying cross-sectional area, the passage 94 offers a offrictional resistance to the how of gases therethrough. inthe forms oforifice construction illustrated in FIGURES l, 3 and 4, the includedangle between the diverging walls may be varied to secure desiredvelocity characteristics for the gases of the blast, and included anglesup to 40 have been found to provide high gas velocities for fiberattenuation purposes.

Another form of annular orifice configuration is illustrated in crosssection in FIGURE In this form, the burner 44b, formed with a combustionchamber 48, has a lower wall 1:?2 of refractory provided with an orificeor passage in this form, the wall 102 is formed with an annulardepending portion 104. The annular passage 1% is formed within thedepending portion 134, the passage being bounded or defined byvertically disposed, comparatively short-length walls 155 which arejoined with arcuate or curved surfaces 16% forming a passage of varyingcross-sectional area to facilitate rapid travel of gases through thepassage.

in this form, the Zone of greatest restriction defined by walls 186 islocated adjacent the outlet of the passage at the lower surface 11% ofthe depending portion 1%. Thus, the curved or arcuately shaped walls 198form a generally divergently shaped passage through which the burnedgases move at high velocities with a minimum of frictional resistance.In order to obtain extremely high velocities, it is desirable that therestricted zone defined by Walls 1% be of relatively short length andshould be of a length sufiicient to maintain a proper width for therestricted zone to maintain control of the depth of the blast anddirection of travel of the gases of the blast under prolongedoperations.

FIGURE 6 is illustrative of another form of orifice or passageconstruction for delivering burned gases from a combustion burner toform an annular blast of high velocity. In this arrangement two passagesand 116 are formed in a depending portion 117 of the annular burner 11%.The passages or orifices 115 and 116 are of generally curved or arcuateconfiguration to provide a curved or annular blast generally concentricwith the periphery of the rotor 20 illustrated in FIGURE 1. Passage 115is defined by walls 125 and 121 preferably convergently arranged towardthe direction of the discharge outlet whereby the maximum restriction tothe fiow of gases is existent at the lower wall 124 of the combustionzone or chamber 127, providing maximum gas velocity at the exit ofpassage 115. The annular gas discharge passage 1316 is defined orbounded laterally by walls 125 and 12.6. The walls 121 and 126 areformed by opposite sides of a member 128 formed of refractory. The uppersurface zone 130 of the partition or member 128 is of curvedconfiguration, the curvature thereof blending With the walls 121 and126. It should be noted that passages 115 and 116 are angularly disposedin a generally convergent relation whereby the burned gases or productsof combustion from the chamber 127 projected through these passages arejoined at a zone immediately beneath wall surface 124 of the burner toform a composite blast of intensely hot burned gases, the zone ofjuncture of the gas streams from passages 115 and 116 occurring at thezone where the primaries or elongated bodies are projected by the rotoror spinner into the blast. The composite blast thus formed by gasesdelivered through passages 115 and 116 may be termed a resultant forceblast which is of exceedingly high velocity and of substantialhorizontal depth at the juncture of the concentric gas streams frompassages 115 and 116. The partition 128 is supported atcircumferentially spaced zones by means of bridges or sections (notshown) joining the partition with the walls and of the passages.

FIGURE 7 is illustrative of fiber-forming apparatus of the generalcharacter shown in FIGURE 1 incorporating a supplementary or auxiliaryburner 135. The blast from the supplemental burner supplies additionalheat at the zone of blast attenuation of the bodies or primaries intofine fibers and is directed toward the outwardly moving primaries orbodies of glass to prevent the projection or penetration of theprimaries or bodies through the main or attenuating blast.

As shown in FIGURES 7 and 8, the burner 137 providing the attenuatingblast is of the same character as the burner 44 shown in FIGURE 1 and isadapted to burn combustible mixture in the chamber or confined zone 138,the burned gases being projected through an orifice 139 as an intenselyhot, high velocity blast B directed into engagement with elongatedbodies or primaries 65 of the fiber-forming material discharged throughsmall openings 7 24 in the spinner 20. The annular orifice or gaspassage 139 may be defined laterally by vertically disposed walls 140 ormay be configurated or shaped as shown in other figures of the drawings.

The supplementary or auxiliary burner 135 disposed beneath the burner137 is formed with a combustion chamber 142 and is equipped with one ormore fuel-andair mixture inlets 144. The burner 135 is generallyannular', and the burner walls have convergent portions 146 providing apassage or orifice 148 through which burned gases from the combustionchamber 142 are projected generally toward the glass primaries or bodies65. The exit zone of the passage 148 may be formed with flared wallsproviding a stream or blast C of gases of a width to engage andinterrupt the horizontal traverse of any primaries or bodies 65 whichmay penetrate through the main blast from the passage 139. 7

Thus, the blast or stream of hot gases projected from the auxiliaryburner 135 provides an antipenetration medium to assure that all of theprimaries or elongated bodies delivered into the main blast from burner137 will be attenuated to fibers. Should any of the primaries orelongated bodies project through the main blast, they will beintercepted by'the supplemental blast from the burner 135 and redirectedthereby into the path of travel of the gases of the main blast andattenuated to fine fibers.

The burned gases projected from the supplemental burner 135 preferablymove or travel at a substantially lesser velocity than the gases of theattenuating blast from the burner 137. The supplemental blast functionsas a medium to prevent penetration through the main blast of thecentrifuged primaries and supplies heat to the primaries, augmenting theheat of the gases of the main blast to foster improved attenuation ofall of the primaries to fine fibers. Fibers formed by this methodusually are longer and finer as the added heat from the antipenetrationburner 135 maintains the fiber-forming material in a softened orattenuable state for a greater distance of travel in'the attenuatingblast.

The antipenetration means may be utilized with various forms or shapesofattenuating blast orifice construction, and the orifice or gas passageof the antipenetration burner may be shaped to various configurations.FIG- URE 9 is illustrative of a supplemental or antipenetration burner155 formed with annular, dual gas passages adapted to produce aresultant force blast in conjunction with a main burner provided with adivergent-walled gas passage or orifice. The burner Ad for producing theattenuating blast is the same as that illustrated in FIGURE 3 andisiformed with a gas discharge passag'eStl' through which burned gasesare discharged at high velocities.

:. The 'antipenetration or supplemental burner 155 is dis posed beneathor adjacent the main burner 44 and is formed with an orificejorgas'passage means similarrto that shown in FIGURE 6. Theorificeconstruction of the supplemental burner in FIGURE 9 includesapartition 157' disposed between walls 158 and1'59 of the'throat portionof the burner. e e 1 The innersurfaces of wall portions 158 and 159andtheadjacent exterior surfaces of thepartition 157 define the gaspassages. or orifices 160 and 161 through which tion so that theg as'es'passing'through each of the passages are combined or joinedsubstantially at theizone of engagement with the attenuating blast fromthe orifice 50 at the regionof the entrance of the primary fibersor'bodies into the main .or attenuating blast.

The gas streams fi'om'the passages 160 and 161 of the annular shape.Joining the gas streams from the burners provides a resultant forceblast of increased heat and of a resultant high velocity which providesfor improved attenuation as the length of the eifective heating zone atthe attenuating region is increased so. that attenuation endures or iscarried on through a greater distance, and the fibers formed are, on theaverage, longer and finer than those produced from a single blast.

It is to be understood that the orifice or gas passage of the mainburner 44 and'the'gas passage of the supplemental burner 155 arepreferably of a curvature concentric with the periphery of the rotor orspinner and provide substantially annular blasts of intensely hot gases,the blast from the supplemental burner 155 being directed generallyradially toward the axis of rotation of the rotor in the region of theprimaries to prevent the projection or penetration of primary fibers orbodies through the main blast. If any primaries or bodies are projectedthrough the main attenuating blast, the blast or gas stream from thesupplemental burner, moving in opposition to the direction traveled bythe primaries, redirects such primaries generally downwardly into themain attenuating blast. By this method, all of the fiberforming materialdistributed by the spinner or rotor 20 is formed into usable fibers.

FIGURE 10 illustrates a supplementary burner 165 having another form ofannular gas discharge passage or orifice 166, the burner 165 being shownin combination with a main burner 4412 having an orifice or passage 10%of the character shown in FIGURE 5 for producing the main attenuatingblast B. In the form of orifice or passage 166 of the supplementalburner 165, the walls of the passage in cross-section are substantiallyparallel to provide a ribbon-like blast C of annular shape in which thegases are directed generally toward the outwardly moving primaries andslightly downwardly of the gases of the attenuating blast from themainburner orificelill).

' The antipenetration blast'C' from the passage or orifice burned gasesfrom the burner chamber 156 are discharged in dual streams. The pairs ofwalls defining the'passages, .160 and 161 preferably are arranged in'con'vergingjrela- 166 is located in the region of the primary fibers orbodies projected by centrifugal force into the main blast and serves todirect downwardly any primaries or bodies which may penetrate throughthe gases of the main blast from the burner 44b. The heat of the gasesof the blast C' augments that of the attenuating blast B to increase theeffective attenuating range of the attenuating blast.

FIGURE ll illustrates in cross section another form of annular main andsupplemental burners wherein the main burner 118 and its gas dischargemeans are of the character shown in FIGURE 6. An annular dependingportion of the burner 118*is formed with convergently arranged gaspassages and 116 defined by a partition or wall 128. The blast B" formedby the joining of the high velocity gas streams moving through passages115 and 116 provides 'a high velocity attenuating means or medium forforming fine fibers from the primaries projected into the blast fromthe. openings in the rotor or spinner 29. i I

Disposed beneath-the burner 118 is an annular burner formed with a'combustion: chamber 176 and a gas discharge passage 178 defined byconvergently arranged,

curved walls 179 and 189; The burner chamber176 is preferably of lesservolume than the combustionchamber of the rnain burner 118, vand theblast or stream C? of supplementary burner 17 5 is inclined slightlydownwardly so that the gases of blast C" join those of the mainattenuating blast andthereby establisha, downwardly extending heatingzone of substantial length so that the fibers being drawn or attenuatedare maintained in an intensely hot attenuating zone for a substantialdistance, a condition which fosters the formation or attenuation oflonger and finer fibers from the primaries.

The main blast B" from the burner 113 is of high velocity due to thejuncture or blending of the gas streams from passages 115 and 116 into acomposite blast, the velocity of which is equal to or exceeds thevelocity of the gases in the individual passages 115 and 116. Throughthe use of the intensely hot blast of this character emanating from theburner 113 in conjunction with the hot gases from the supplemental orantipenetration burner 175, substantially more material may beattenuated to fine fibers per unit of time than is possible with a blastfrom a conventional orifice, an arrangement which facilitates economicalproduction of tine fibers.

FIGURE 12 illustrates a form of apparatus of the invention wherein agenerally annularly shaped gas discharge zone of an annular burner 36!)is partitioned or subdivided by radially disposed walls to form anannular blast made up of a plurality of individual, high velocity gasstreams or blasts from the passages defined by the radially disposedwalls. With particular reference to FIGURES 12 through 14, the burner369, similar to burner 44, surrounds a rotor or spinner 392, the latterhaving openings 304 in the peripheral zone or band 305 through whichprimaries 307 are projected by rotation of the spinner 392. The burner360 is formed with an annular combustion chamber 310 defined byrefractory walls 312. The lower wall of the chamber 31%} is formed withan annular passage 314.

Disposed beneath the refractory wall 315 of the burner 306 is atemperature-controlled gas discharge passage or orifice construction318. The arrangement 318 is formed with inner and outer wall portions320 and 322 joined together by circumferentially spaced, radiallydisposed partitions 326. The generally rectangular passages 323 formedby the walls 32G, 322 and partitions 326 are in communication with thepassage 314 through which gases from the chamber 310 are projecteddownwardly at high velocity to establish a generally annular blastdirected downwardly past the peripheral band of the rotor 302 and intoattenuating engagement with the primaries 307.

The gas passage construction 318 is formed with concentrically arrangedwalls 330 and 331, an upper wall 333 and a bottom wall 335. The walls336 and 331 form with the wall portions 320 and 322 annularly shapedzones, channels or chambers 337 and 333. These channels, zones orchambers are adapted to accommodate a cooling fluid ortemperature-controlling medium to maintain the walls defining the blastorifices or passages 328 at a safe operating temperature. Such controlmay be utilized to regulate the temperature of the blasts to a limitedextent in the event that such control is desired. The radially disposedpartitions or walls 326 of adjacent orifices or passageways 328 arespaced to provide connecting channels or passages 340 establishingcommunication between the chambers or zones 337 and 338. The coolingwater or other temperature-controlling medium may be introduced into theouter chamber 338 through an inlet pipe or duct 342. The cooling Waterin chamber 338 may circulate freely around the walls defining theindividual gas passages 328 by way of the connecting passages 349 andthe innermost, annular coolant chamber 337. The cooling water or mediummay be conducted away from the orifice construction 318 through an 10outlet pipe 344. The construction defining the restricted gas passages328, cooled by a circulating medium as shown in FIGURES 12 through 14,enables the use of a metal-walled construction for guiding the intenselyhot, high velocity burned gases into attenuating engagement with theprimaries 367.

FIGURE 15 is a horizontal, sectional view of a blast orificeconstruction similar to FIGURE 13. In the arrangement shown in FIGURE14, the water-cooled orifice or gas passage construction is inclusive ofinner and outer walls 330 and 331. The individual blast-definingpassages or orifices are spaced from the walls 338 and 331 and includeconcentric wall portions 35% and 351. Disposed between the walls 359 and351 and spaced circumferentially are radially disposed walls orpartitions 353. The radial walls 353 and the concentric wall portions350 and 351 form passages 355 through which burned gases or products ofcombustion from a burner chamber 311} of the character shown in FIGURE14 are discharged to form individual, high velocity blasts arranged inan annular pattern.

The arrangement shown in FIGURE 15 is cooled and the temperature iscontrolled by a circulating, cooling medium such as water. The walls 330and wall sections 356 define a generally annular chamber or passage 356,and the walls 331 and wall sections 351 define a generally annularchamber 357. Inlet and outlet ducts, designated respectively 360 and361, convey water or other cooling medium into and away from the chamber357. Inlet and outlet ipes 364 and 365 convey water or cooling mediuminto and away from the chamber 356.

no circulation of water around the walls 359 and 351 reduces or controlsthe temperature or" these walls and the partitions 353 defining theindividual gas passages 355.

It is apparent that, within the scope of the invention, modificationsand difierent arrangements may be made other than is herein disclosed,and the present disclosure is illustrative merely, the inventioncomprehending all variations thereof.

I claim:

A method of producing fibers from heat-softenable fiber-forming materialincluding the steps of delivering a stream of the material onto arotating surface whereby the material is distributed outwardly of thesurface in the form of primary filaments, burning a combustible mixturein a first annular region to establish an intensely hot, annularlyshaped gaseous blast, directing the blast into engagement with theprimary filaments in directions substantially normal to the paths ofmovement of the filaments to attenuate the same to fibers, burningcombustible mixture in a second annular region to establish a secondgaseous blast, and directing the gases of the second blast generallytoward the rotating surface whereby filaments penetrating theattenuating blast are redirected by the second blast into theattenuating blast.

References Cited in the file of this patent UNITED STATES PATENTS2,499,218 Hess Feb. 28, 1950 2,607,975 Stalego Aug. 19, 1952 2,609,566Stayter et al. Sept. 9, 1952 2,624,912 Heymes et al. Jan. 13, 19532,643,415 Stalego June 30, 1953 2,645,814 Stalego July 21, 19532,646,593 Downey July 28, 1953

